This proposal focuses on the human respiratory pathogen, Mycoplasma pneumoniae. Emphasis is directed at analyzing mycoplasma binding sites (ligands, adhesins) responsible for surface parasitism of respiratory cells; purifying and characterizing host cell receptors that mediate this cytadsorption; generating monospecific and monoclonal antibodies against key M. pneumoniae membrane proteins; and examining membrane properties of mycoplasmas in order to assess topography and function of mycoplasma adhesins and accessory proteins. These experimental approaches require the use of radiolabeling techniques, acrylamide gel electrophoresis, column chromatography, basic microbiological-tissue culture procedures and handling of experimental animals. Also generation of monospecific and monoclonal antibodies will be necessary along with immunoferritin electron microscopy. This infectious disease model should provide fundamental information that clarifies host-parasite (membrane-membrane) interactions at biochemical-immunological-molecular levels. Effort is made to demonstrate the unique advantages of this system as an important biological resource in the study of human airway disease and in the analysis of structural-functional interactions among membrane macromolecules.